Pressure control for paper-folding machines



Dec. 7, 1943,

G. W. SCHMIDT PRESSUREv CONTROL FOR PAPER FOLDING MACHINES Filed Nov. 30, 1940 2 She'et-Sheet -1' Dec. 7, 1943.

. e. w. SCHMIDT PRESSURE CONTROL FOR F APER- FOLDING MACHINES Filed Nov. '50 1940 2 Sheefs-Sheet 2 Fly lnven tor Gerald Will/am Schmidt fly A ttor n ys Patented Dec. 7, 1943 PRESSURE CONTROL FOR PAPER-FOLDING MACHINES Gerald W. Schmidt, Camas, Wash, assignor to Crown Zellerbach Corporation, San Francisc Calif., a corporation of Nevada Application November 30, 1940, Serial No. 368,015 2 Claims. (01. 270 -80) This invention relates to sheet folders or paperfolding machines of the type familiarly known among paper manufacturers as a Brannon. folder.

In a folder of this type the sheet or sheets to be folded are positioned over a pair of press rolls and a relatively thin blade, commonly called a tucker blade, presses the sheets of paper down between the rolls causing a fold to be made on the line formed by the engagement of the edge of the tucker blade with the sheets. As soon as thefold is made the tucker blade is raised from the sheets while oppositely-rotating press rolls draw the folded sheet, or sheets, down between the rolls by which the folded sheet is droppedonto a suitable conveyor below. A second sheet or group of sheets is then positioned above the rolls beneath the tucker blade and the operation repeated. Oneof the problems presented in such a folding machine is to have the press rolls exert sufficient pressure to form a definite crease in the sheets after having been inserted between them by the tucker blade and still not cause any wrinkling of the sheets as pulled down between the press rolls and while the tucker blade is withdrawn. This difficulty is generally met with, forv example, in folding a quire of paper. In such case wrinkling of at least some of the sheets is very likely to take place.

In attempting to overcome this difliculty it occured to me that if the pressure exerted by the two engaging rolls could be varied and properly controlled during the successive stages of the operation, the wrinkling of the sheet or sheets after the fold had initially been made might be avoided.

Accordingly the object of this invention is to provide means, associated with the press rolls of a folding machine such as the Brannon folder, whereby the pressure applied to the rolls will be limited to the short interval required to form a definite fold in the sheet or quire, and whereby such pressure thereupon will immediately be released or reduced so as to allow the folded sheet or quire to be fed on through the rolls without being wrinkled.

This object I am able to attain by having one of the press rolls mounted so as to be slightly movable towards or away from the other press roll, and by employing mechanism, includinga suitable arm and cam, for positioning the movable roll with respect to the other roll, and by otherwise controlling and synchronizing such rolls in the manner hereinafter briefly described with reference to the accompanying drawings.

In the drawings:

Figure 1 is a schematic side elevation of a paper folding machine, such as the Brannon folder, embodying the features of my invention, in combination with a rotary paper cutter;

Figure 2 is a sectional elevation taken on the line 22 of Figure 3 but drawn to a larger scale, the tucker blade supporting frame having been removed for clarity; and I Figure 3 is -a partial sectional plan taken on the line 33 of Figure 2.

In the paper-folding machine illustrated the flat paper sheets are fed or delivered by a conveyor belt from the sheet-cutting knife V and brought to rest above the press rolls A and- B.

When the sheets have been positioned over these rolls, a reciprocating transverse steel blade C, known as a "tucker blade and actuated through the medium of the cam U and follower R, is caused to'descend to the position shown in Figures 1 and 2, to insert the sheets between the rubber press rolls A and B. These pressrolls are rotated towards each other at the -same rate of speed by the meshing gears K and K and are driven by any suitable means (not shown). The shafts of the press rolls A and B are journaled in bearings E and F, respectively, at each end. These bearings are supported in theside frames G of the machine in the special recesses H and J. The recess H in each frame provides a close fit for the bearing E of the fixed press roll A, but the recess J is made of sufiicientsize, as shown'in Figures 2 and 3, to provide for slightly horizontal movement of the'bea'ring F. Each side frame G is flanged at the top and around the recesses H and J, providing side and bottom walls for these recesses.

A bell crank I is pivotally mounted on a casting 3 which is bolted to the side frame G. On one end of the bell crank I a cam follower roll 4 is mounted by means of a suitable shoulder bolt or stud. This cam follower 4 rides on the cam 8. The other end of the bell crank l terminates in an eye which is drilled and tapped to receive a cap screw 5. The screw 5 supports a pressure block 6 which bears against the shaft 1, the pressure block 5 being drilled on one face to receive the cap screw 5 and having the opposite face shaped to correspond to the curvature of shaft 1.

A plate I I is attached to the side of the bearing F, as shown in Figures 2 and 3, and this plate is threaded to receive one end of a rod l 2. The rod movement and resulting pressure exerted by the I2 extends through the side wall of recess J and direction opposed to the force exerted by the bell crank l, and thus normally space press-roll B from press-roll A.

The cam 8 is driven by any suitable means, such as a sprocket and chain 9 (Figure 3) and, as will be seen from Figure 2, whenever the lobe or extended portion of the periphery of cam 3 contacts the cam follower 4, the bell crank I will cause the press roll B to press against the companion press roll A; but, when the remaining periphery of the H cam 8 is in contact with cam follower 4 this'pressure of press roll B against press roll A will be released and the spring IE! will then be permitted to act to move the press roll B slightly away from the press roll A to the extent permitted by the cam 8.

Cam 8, and cam U which actuates the tucker blade C, are driven at the same speed from a common source of power (not shown), and the two cams are 50 arranged and synchronized that the pressure between the two press rolls A and B will be exerted soon after the tucker blade is dropped, thus producing a fold in the sheets, and so that the pressure will then immediately be released while the folded and creased sheets are drawn down between the press rolls A and B, which will then function merely as draw-rolls, and while the tucker blade is raised.

While I have described the operation of the pressure control at one side of the machine only and thus only at one end of the press roll B, it is to be understood that the same means are provided and the same action takes place at the other end of the press roll B where a similar bell crank and cam are mounted so that the two bell cranks move in unison.

The cams 8 and U for the pressure control and tucker blade are preferably driven from the driving mechanism operating'the revolving cutter knife V (Fig. 1). Thus a chain such as indicated at in Fig. 1, may connect the cams 8 with the drive for the cutter knife V and similar means (not shown) may connect cams 8 and cams U so that the tucker blade operating means and the pressure control mechanism will be synchronized as mentioned above. The cutter knife V cooperates with a fixed knife W in the usual manner to cut the paper into the desired sheets to be folded and the travel of the paper sheets is indicated by the line 2| and the arrow 22. It has also been found desirable to provide the two rubber press rolls A and B with a slight crown to insure even pressure throughout their extent, and particularly in the central area where greatest wear occurs. It is possible of course to make various modifications in the actual construction of the pressure control as described by me without departing from the principle of my invention and it is not my intention to limit my invention otherwise than as stated in the attached claims.

Iclaim:

1. In a paper folding machine of the character described, a pair of press rolls, means for rotating said press rolls, a movable bearing for one of said press rolls, means adapted to move said roll with the movable bearing away from the other roll, pressure control mechanism for causing the roll with said movable bearing to be moved against the other roll, a tucker blade inserting sheets of paper between said rolls, cam means for operating said tucker blade, driving means for said pressure control mechanism and said tucker blade operating means, said pressure control mechanism and said tucker blade operating means so arranged and synchronized as to cause the increased pressure between said rolls to be exerted when the tucker blade inserts the paper between the rolls and. then to be released to permit the paper to pass between the rolls without wrinkling and the tucker blade to'be withdrawn from said paper and rolls.

2. In a paper folding machine of the character described, a pair of press rolls, means for rotating said press rolls, a slidable bearing for one of said press rolls, spring means adapted to move the roll with the slidable bearing awayfrom the other roll, pressure control cam mechanism for causing the roll with said slidable bearing to be moved against the other roll, a tucker blade insorting sheets of paper between said rolls, cam means for operating said tucker blade driving means for, said pressure control mechanism and said tucker blade operating means, said pressure control mechanism and said tucker blade operating means so arranged and synchronized as to cause the increased pressure between said rolls to be exerted when the tucker blade inserts the paper between the rolls and then to be, released to permit the paper to pass between the rolls without wrinkling. andthe tucker blade. to be withdrawn from said paper and rolls.

GERALD W. SCHMIDT. 

